A.H.
Just be patient. A healthy baby will not starve himself. I've had a couple of my babies do this and I just don't offer them anything else until they nurse. Once he gets hungry enough, he'll be happy to nurse. I would be on the lookout for teeth, personally.
In the meantime, pump to keep your supply up. Oh...and if he suddenly decides he wants to nurse right after you've just pumped, don't be afraid to go ahead and nurse him. You body will make more. Milk doesn't store in the breast, at least the majority of a feed anyway. The early foremilk does, but the fatty, nutrient rich stuff is made as you are nursing and the lactating breast is never truly empty.